120 CHEMICAL ENGINEERING in regard to capacity, head and speed and the reduced efficiency under conditions other than those for which the pump was designed. PISTONLESS PUMPS Pulsometers Pulsometers (Fig. 13) are pistonless steam-operated displacement pumps with two chambers, AA. The steam enters these chambers alternately and is controlled by a ball or flap valve C. It enters one chamber and forces the water contained therein out through a check valve F to the discharge pipe H until the steam enters the discharge pipe where it is condensed and produces a suction effect which throws the valve C and draws up the water through the suction valves. J is an air chamber. Notwithstanding their low efficiency they are used extensively in. mines, at railroad watering stations, for draining building pits, etc. Suction lift, up to 26 ft., max., preferably 7 to 14 ft.; discharge head, up to 150 ft. The steam pressure must be about 50 per cent higher than the total water pressure. Low heads give a lower efficiency than high heads. The discharge water is heated 3.5°F. for a head of 30 ft. For every additional 30 ft., add 1.5°. For water-temperatures in excess of 120°F., no suction lift is obtainable. The steam consumption by volume is from 2 to 3 times the water displacement. Wood finds duties varying from 10.5 to 13.4 million ft.-lb., the higher figure corresponding to the higher head. This « corresponds to a steam con- « sumption of 190 to 150 Ib. per horsepower per hour. A duty of 21,345,000 ft.-lb. has been found for total lifts of 102.6 ft. „ Compressed air pumping may be accomplished by displacement apparatus (eggs, montejus, etc). The air pressure is applied directly on the liquid in the tank. Two displacement tanks are generally used, alternately filling and discharging. The valve distributing the compressed air may be operated by hand, floats, by the drop in air pressure upon discharge of liquid contents, the air following the liquid through the line, or some suitable timed mechanism. If sufficient submergence can be had the tanks are submerged and the liquid will FIG. 13.—Pulsometer. FIG. 14.—Acid egg.